Agricultural Apparatus For Sensing And Providing Feedback Of Soil Property Changes In Real Time

ABSTRACT

An agricultural system includes an agricultural row unit movable on a field between a first soil condition and a second soil condition, the first soil condition having a different soil hardness than the second soil condition. A down-pressure actuator applies an initial first pressure associated with the first soil condition. A soil-hardness sensing device is positioned at a distance D forward of the row unit and outputs a soil-hardness change signal when detecting a change from the first soil condition to the second soil condition. At least one memory device stores instructions that, when executed by at least one processor, cause the down-pressure actuator to change, in response to receiving the soil-hardness change signal, the initial first pressure to a different second pressure when the row unit encounters the second soil condition.

FIELD OF THE INVENTION

The present invention relates generally to agricultural equipment and,more particularly, to a row crop implement having a soil sensor forproviding down-pressure control feedback in real time.

BACKGROUND OF THE INVENTION

In agricultural operations, it is known to measure a force exerted ongauge wheels of an agricultural implement (e.g., a row crop planter),with a load cell or some other device. Based on this force, a signal istransmitted to an actuator that exerts a down-pressure force on theimplement. The signal causes the actuator to change the down-pressureforce, in response to a change in soil conditions, and achieve a desiredforce on the row crop planter.

Moreover, it is common in agricultural operations for small, localized,and compacted soil areas to be formed by tire tracks, topographychanges, or soil type. These compacted soil areas cause the soilconditions to change, for example, from a hard soil condition to a softsoil condition. Current agricultural systems, however, react to signalscaused by a compacted soil area after the implement has already passedover that compacted soil area. As such, current agricultural systemsfail to apply a correct level of pressure for the soil that isimmediately beneath the implement. Instead, when a new soil condition isdetected in a particular field location, current agricultural systemsapply the level of pressure associated with the new soil conditioneither before or after the implement has passed the particular fieldlocation. This results in inefficient and/or improper soil preparationfor agricultural applications, such as planting or tilling, which, inturn, causes a decrease in crop quality and volume.

SUMMARY OF THE INVENTION

In accordance with one embodiment, an agricultural system includes anagricultural row unit movable on a field between a first soil conditionand a second soil condition, the first soil condition having a differentsoil hardness than the second soil condition. A down-pressure actuatorapplies an initial first pressure associated with the first soilcondition. A soil-hardness sensing device is positioned at a distance Dforward of the row unit and outputs a soil-hardness change signal whendetecting a change from the first soil condition to the second soilcondition. At least one memory device stores instructions that, whenexecuted by at least one processor, cause the down-pressure actuator tochange, in response to receiving the soil-hardness change signal, theinitial first pressure to a different second pressure when the row unitencounters the second soil condition.

In accordance with another embodiment, an agricultural system includes aplurality of row units positioned in a side-by-side arrangement andattachable to a towing frame, the plurality of row units being movableon a field between soil conditions of varying soil hardness. Theplurality of row units includes a first group of row units positionedinside a towing-vehicle width and a second group of row units positionedoutside the towing-vehicle width. A hydraulic actuator is mounted on andapplies down pressure to each row unit of the plurality of row units,the hydraulic actuator being adjustable to a frequency F and initiallyapplying a first down pressure. A first soil-hardness sensing device ispositioned at a distance X1 forward of at least one row unit of thefirst group of row units, the first soil-hardness sensing deviceoutputting a first soil-hardness change signal when detecting a changein soil hardness inside the towing-vehicle width. A second soil-hardnesssensing device is positioned at a distance X2 forward of at least onerow unit of the second group of row units, the second soil-hardnesssensing device outputting a second soil-hardness change signal whendetecting a change in soil hardness outside the towing-vehicle width. Atleast one memory device stores instructions that, when executed by oneor more processors, cause the hydraulic actuator of respective ones ofthe plurality of row units to change, in response to receiving at leastone of the first soil-hardness change signal and the secondsoil-hardness change signal, the first pressure to a second pressure.

In accordance with yet another embodiment, an agricultural systemincludes an agricultural row unit movable on a field between a firstsoil condition and a second soil condition, the first soil conditionhaving a different soil hardness than the second soil condition. Adown-pressure actuator applies pressure to the row unit, thedown-pressure actuator initially applying a first pressure associatedwith the first soil condition. A velocity sensing device detects avelocity Q of the row unit. A soil-hardness sensing device is positionedat a distance D forward of the row unit and encounters the second soilcondition at an initial time prior to the row unit encountering thesecond soil condition at a subsequent time. The soil-hardness sensingdevice outputs a soil-hardness change signal when detecting a changefrom the first soil condition to the second soil condition. At least onememory device stores instructions that, when executed by at least oneprocessor, cause the down-pressure actuator to change, in response toreceiving the soil-hardness change signal and based on the velocity Qand the distance D, the first pressure to a second pressure at thesubsequent time when the row unit encounters the second soil condition.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may best be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich:

FIG. 1 is a perspective view of a soil-hardness sensing device attachedto a planting row unit.

FIG. 2 is a schematic side elevation illustrating the soil-hardnessdevice attached to the planting row unit.

FIG. 3 is a schematic diagram illustrating the determination ofhydraulic pressures for a planting row unit.

FIG. 4A is a side elevation of an agricultural system moving over softsoil conditions.

FIG. 4B is a side elevation of the agricultural system of FIG. 4A inwhich a soil-hardness sensing device is moving over hard soilconditions.

FIG. 4C is a side elevation of the agricultural system of FIG. 4B inwhich a planting row unit is moving over the hard soil conditions.

FIG. 5A is a schematic side elevation illustrating sensing of soilconditions and determining of hydraulic pressures for a planting rowunit.

FIG. 5B is a flowchart of an algorithm for adjusting a pressure appliedto a soil-hardness sensing device.

FIG. 5C is a flowchart of an algorithm for adjusting a user-definedvariable associated with a pressure applied to a planting row unit.

FIG. 5D is a flowchart of an algorithm for adjusting a user-definedvariable associated with a pressure applied to a row-clearing unit.

FIG. 6A is a top elevation illustrating an agricultural system in whicha plurality of planting row units are adjusted by two soil-hardnesssensing devices.

FIG. 6B is a side elevation illustrating the agricultural system of FIG.6B.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Although the invention will be described in connection with certainpreferred embodiments, it will be understood that the invention is notlimited to those particular embodiments. On the contrary, the inventionis intended to cover all alternatives, modifications, and equivalentarrangements as may be included within the spirit and scope of theinvention as defined by the appended claims.

Referring to FIG. 1, an agricultural system 100 includes a soil-hardnesssensing device 102 attached in front of an agricultural row unit 104(also referred to as a planting row unit) via a towing frame 106. Thetowing frame 106 is generally a common elongated hollow frame that istypically hitched to a tractor by a draw bar. The towing frame 106 isrigidly attached to a front frame 108 of a four-bar linkage assembly 110that is part of the row unit 104. The four-bar (sometimes referred to as“parallel-bar”) linkage assembly 110 is a conventional and well knownlinkage used in agricultural implements to permit the raising andlowering of tools attached thereto.

As the planting row unit 104 is advanced by the tractor, a pair ofcooperating toothed clearing wheels 122 work the soil and then otherportions of the row unit, such as a V-opener disk 112, part the clearedsoil to form a seed slot, deposit seed in the seed slot and fertilizeradjacent to the seed slot, and close the seed slot by distributingloosened soil into the seed slot with a closing wheel 114. According toone example, the closing wheel 114 is a CUVERTINE™ closing wheel sold bythe assignee of the present application. The CUVERTINE™ closing wheel isan efficient toothed wheel in-between a spading wheel and a rubberwheel.

A gauge wheel 116 of the planting row unit 104 determines the plantingdepth for the seed and the height of introduction of fertilizer, etc.One or more bins 118 on the planting row unit 104 carry the chemicalsand seed that are directed into the soil.

The planting row unit 104 is urged downwardly against the soil by itsown weight. To increase this downward force, or to be able to adjust theforce, a hydraulic or pneumatic actuator 120 (and/or one or moresprings) is added between the front frame 108 and the four-bar linkageassembly 110 to urge the planting row unit 104 downwardly with acontrollable force. Such a hydraulic actuator 120 may also be used tolift the row unit off the ground for transport by a heavier, stronger,fixed-height frame that is also used to transport large quantities offertilizer for application via multiple residue-clearing and tillage rowunits. According to one example, the hydraulic actuator 120 is an RFX™system sold by the assignee of the present application. The RFX™ systemincludes a down-pressure actuator that is a compact, fast actionactuator, and that is remotely controlled. The RFX™ system includes annitrogen pressure-vessel that is integrated with the down-pressureactuator. According to other examples, the hydraulic or pneumaticactuator 120 may be controlled to adjust the downward force fordifferent soil conditions such as is described in U.S. Pat. Nos.5,709,271, 5,685,245 and 5,479,992.

The planting row unit 104 further includes a row-clearing unit 122having a pair of rigid arms 124 adapted to be rigidly connected to thetowing frame 106. According to one example, the row-clearing unit 122 isa GFX™ system (i.e., ground effects row cleaner), which is sold by theassignee of the present application, that is a hydraulically-controlledrow cleaner. The GFX™ system is a hydraulically-controlled row cleanerwith spring upward pressure and hydraulic down pressure. Furthermore,the GFX™ system is remotely adjusted.

At the bottom of the row-clearing unit 122, the pair of cooperatingtoothed clearing wheels 126 are positioned upstream of the V-opener disk112 of the planting row unit 104. The clearing wheels 126 are arrangedfor rotation about transverse axes and are driven by the underlying soilas the wheels are advanced over the soil. The illustrative clearingwheels 126 are a type currently sold by the assignee of the presentinvention under the trademark TRASHWHEEL™. The clearing wheels 126cooperate to produce a scissors action that breaks up compacted soil andsimultaneously clears residue out of the path of planting. The clearingwheels 126 kick residue off to opposite sides, thus clearing a row forplanting. To this end, the lower edges are tilted outwardly to assist inclearing the row to be planted. This arrangement is particularly wellsuited for strip tilling, where the strip cleared for planting istypically only about 10 inches of the 30-inch center-to-center spacingbetween planting rows.

The soil-hardness sensing device 102 has a first linkage 130 with anattached blade 132 and a second linkage 134 with an attached gauge wheel136. According to one example, the linkages are medium FREEFARM™linkages sold by the assignee of the present application. The FREEFARM™linkages are generally a modular set of parallel linkages used fordifferent purposes. Also, according to one example, the soil-hardnesssensing device 102 is a FORESIGHT AND CFX™ ground hardness sensor thatis sold by the assignee of the present application.

The two linkages 130, 134 are parallel to each other and each has a downpneumatic pressure that is controlled independently. Under constantpneumatic pressure, when the soil-hardness sensing device 102 is movedthrough the field, the blade 132 penetrates the soil deeper in soft soiland shallower in hard soil. However, the wheel 136 rides on the soilsurface regardless of the type of soil.

Each linkage 130, 134 has a high quality all-stainless steel linearposition sensor 138, 140 enclosed in a protecting housing, with a cable142, 144 routed to a central processing unit (CPU) 146, which includes amemory device for storing instructions and at least one processor forexecuting the instructions. When the blade 132 or the wheel 136 moves, acorresponding change in value is recorded on the respective positionsensors 138, 140. The two values from the position sensors 138, 140 areoutputted as fast as approximately 1,000 times/second and are fed assoil-hardness signals to the CPU 146, which is a rugged outdoor-ratedprogrammable logic controller that measures the difference in the twovalues in real time.

In the illustrated example, the CPU 146 is positioned on the plantingrow unit 104. However, in other embodiments the CPU 146 may bepositioned remote from the planting row unit 104, e.g., in a tractorcabin, on a different planting row unit of a side-by-side row unitarrangement, etc. Furthermore the processor and the memory device of theCPU 146 can be located in the same place, e.g., on the planting row unit104, or in different places, e.g., the processor can be located on theplanting row unit 104 and the memory device can be located in thetractor cabin.

The CPU 146 averages the values over a predetermined time period (e.g.,0.25 seconds), executes an algorithm with filtering effects (e.g.,removes conditions in which a rock is hit by the soil-hardness sensingdevice 102), and provides real-time measurement of the soil hardness.The CPU 146 optionally receives other user-controllable variables foradjusting/tuning the agricultural system 100. For example, theuser-controllable variables include values for different residue levels,different initial conditions, etc.

Referring to FIG. 2, the agricultural system 100 receives hydraulicfluid from a hydraulic source, typically located in the tractor, at ahydraulic input pressure P0. The hydraulic fluid is directed to each oneof a plurality of hydraulic control valves V1-V3. The CPU 146 outputs arespective signal S1-S3 to the control valves V1-V3, which create aproportional output/change in the pressure of hydraulic circuits,virtually instantaneously changing the pressure in real time as theagricultural system 100 moves through a field. The pressure changes areuseful, for example, when the agricultural system 100 encountershardened soil areas in which combines or grain carts have previouslycompacted the soil. The agricultural system 100 optimizes the pressureto achieve a desired depth control by applying the right amount ofpressure at the right time.

To achieve the right amount of pressure for each controllable component(e.g., the hydraulic actuator 120, the row-clearing unit 122, and thesoil-hardness sensing device 102), the CPU 146 outputs the respectivesignals S1-S3 to the associated control valves V1-V3. For example, inresponse to receiving a first signal S1 from the CPU 146, a firstcontrol valve V1 outputs a proportional first pressure P1 to thehydraulic actuator 120 (e.g., RFX™ system) for urging the planting rowunit 104 downwardly. Similarly, in response to receiving a second signalS2 from the CPU 146, a second control valve V2 outputs a proportionalsecond pressure P2 to the row-clearing unit 122 (e.g., GFX™ system). TheRFX™ system 120 and the GFX™ system 122 are controlled independentlybecause residue typically exhibits non-linear behavior. In other words,the independent control of the two systems 120, 122 is likely to achievebetter depth-control results.

A third control valve V3 receives a third signal S3 from the CPU 145, inresponse to which the third control valve outputs a proportional thirdpressure P3 to the soil-hardness sensing device 102 (e.g., FORESIGHT ANDCFX™ system). The control valves V1-V3 return hydraulic fluid to thehydraulic source at a return pressure PR. Respective transducers foreach of the control valves V1-V3 may be used to verify that hydraulicoutput matches the desired value. If the hydraulic output does not matchthe desired value, the hydraulic output is corrected. Furthermore, eachof the control valves V1-V3 has a respective valve response time T1-T3,which are discussed in more detail below in reference to determining thetiming of applying the appropriate pressures P1-P3.

The CPU 146 further receives an input speed signal SQ indicative of aspeed Q of the agricultural system 100, which moves typically at about 6miles per hour, i.e., about 8.8 feet per second. As discussed in moredetail below, the speed signal SQ is used to determine the values ofpressures P1-P3 based on current soil conditions. Furthermore, asdiscussed in more detail below, the CPU 146 further outputs two signals,a sensor signal SCFX to the soil-hardness sensing device 102 and aclosing wheel SCW to the closing wheel 114.

The soil-hardness sensing device 102 is positioned in front of theplanting row unit 104 at a distance D (which is measured generally froma center line of the blade 132 to a center line of the V-opener disk112), which can be obtained based on the following formula:

Q (speed)=D (distance)/T (time interval)   Equation 1

Thus, the distance D is calculated as follows:

D=Q*T   Equation 2

If D is a known distance (e.g., the distance between the sensed positionand position where seed-depositing position) and the speed Q is alsoknown, changes in soil conditions can be anticipated in real time priorto the planter row unit 104 arriving to the particular soil-change area.For example, assuming that Q is approximately 8.8 feet per second and Tis approximately 0.25 seconds, D should be approximately equal to orgreater than 2.2 feet. In other words, the minimum distance for D shouldbe approximately 2.2 feet. If D is greater than the minimum value (e.g.,D is greater than 2.2 feet), the agricultural system 100 is calibratedto account for the additional distance. For example, the CPU 146 willsend the respective signals S1, S2 to the associated control valves V1,V2 only after a predetermined period of time Tact, as discussed in moredetail below.

Pressures P1 and P2 are to be applied only when matched with thecorresponding soil conditions. For example, P1 and P2 are increasedexactly at the time when harder soil conditions are encountered directlybelow the planting row unit 104. To properly time the change inpressures P1 and P2 correctly, a time variable R refers to the latentprocessing speed of CPU 146 and accounts for the time between (a)receiving an input signal by the CPU 146, (b) sending output signals S1,S2 by the CPU 146, and (c) responding to the output signals S2, S2 bythe control valves V1, V2 with respective outputting pressures P1, P2.

It is noted that each of the control valves V1, V2 has a minimum inputtime Tmin, and that the distance D (e.g., as measured between the centerof the blade 232 and the center of the V-opener disk 212) is directlyproportional to the speed Q multiplied by the minimum input time Tmin ofthe respective control valve V1, V2. It is further noted that atheoretical time Ttheor is directly proportional to the distance Ddivided by the speed Q (i.e., D/Q), and that an actual time Tact isdirectly proportional to the theoretical time Ttheor minus the timevariable R (i.e., Ttheor−R). Based on these conditions, for outputtingpressures P1 and P2, the CPU 146 holds in memory output signals S1 andS2 for a time duration that is equal to the actual time Tact. After theactual time Tact has elapsed, the CPU 146 outputs signals S1 and S2,respectively, to the control valves V1, V2, which respond by outputtingpressures P1, P2. Optionally, signals S1 and S2 are outputted as signalsranging between 0-10 volts.

Referring to FIG. 3, a global positioning system (GPS) provides a GPSsignal indicative of the speed Q to the tractor. Optionally, forexample, the speed Q can be generated from a radar system. The speed Qis inputted to the CPU 146, along with the soil-hardness signalsreceived from the position sensors 138, 140. Based on the speed Q andthe soil-hardness signals, the CPU 146 outputs signals Si and S2 to thecontrol valves V1, V2, which output proportional pressures P1 and P2 foradjusting, respectively, the RFX™ system 120 and the GFX™ system 122.

Referring to FIGS. 4A-4C, the agricultural system 100 encounters varioustypes of soil-hardness conditions, which, for ease of understanding,will include soft soil conditions and hard soil conditions. The softsoil conditions exemplify typical soil conditions, and the hard soilconditions exemplify compacted soil areas, e.g., areas compacted by tiretracks of tractors or combines.

Referring specifically to FIG. 4A, the agricultural system 100 is movingforward at a speed Q over an initial soil area having only soft soilconditions. Based on the soft soil, the blade 132 penetrates the soil ata distance X1 lower than the wheel 136 (which rides on the soilsurface). The distance X1 is the difference between the position sensors138, 140. In accordance with the distance X1, which is associated withsoft soil conditions, corresponding pressures P1 and P2 are applied tothe hydraulic actuator 120 and the row-clearing unit 122.

Referring specifically to FIG. 4B, the blade 132 and the wheel 136 (butnot the planting row unit 104) are now moving over a soil area of hardsoil conditions. Because the soil is now much harder than the previoussoil area, the blade 132 cannot penetrate the soil as much as in theprevious soil area. As such, the blade 132 rises higher relative to thesoil surface and penetrates the soil only at a distance X2 lower thanthe wheel 136 (which continues to ride on the soil surface). Thedistance X2 is the distance determined by the CPU 146 based on thecorresponding change in value outputted by the position sensors 138,140. However, although the distance X2 (which is associated with hardsoil conditions) is different than the previous distance X1 (which isassociated with soft soil conditions), the corresponding pressures P1and P2 are not changed, yet, because the planting row unit 104 has notreached the hard-soil area.

Referring specifically to FIG. 4C, the planting row unit 104 is nowmoving over the hard-soil area, which the blade 132 and the wheel 136have already passed. At this point in time, and only at this point intime, the pressures P1 and P2 are increased to maintain the desireddepth level. Thus, although the soil-hardness sensing device 102 hasreached, again, soft soil conditions that allow the blade 132 topenetrate the soil at the previous distance X1, the pressures P1 and P2are adjusted in accordance with the hard soil conditions.

Referring to FIG. 5A, another exemplary soil-hardness sensing device 202is attached to a towing frame 206 and includes a planting row unit 204having a V-opener disk 212, a closing wheel 214, and a row-unit gaugewheel 216. The planting row unit 204 further includes a hydraulicactuator 220 that responds to a pressure P1 and a row-clearing unit 222that responds to a pressure P2. The soil-hardness device 202 and theplanting row unit 204 are generally similar to the soil-hardness device102 and the planting row unit 104 described above in reference to FIGS.1-4C, except for any changes described below.

In this embodiment the soil-hardness device 202 can be a device that isalready included in the planting row unit 204, such as a cutting coulterrunning directly in-line with the planter row unit or a fertilizeropener positioned off to a side of the planted area. Thus, assuming aside-by-side arrangement of row units, the soil-hardness device can takethe form of a fertilizer opener or a no-till cutting coulter in front ofor to the side of every row unit.

The soil-hardness device 202 includes a blade 232 and a soil-hardnessgauge wheel 236. The blade 232 is attached to a blade arm 260 and thesoil-hardness gauge wheel 236 is attached to a wheel arm 262. The wheelarm 262 is biased down by a spring 264 and pivots relative to the bladearm 260. An angular encoder 266 measures changes in an angle θ betweenthe blade arm 260 and the wheel arm 262. The angle θ is directlyproportional to the depth of the blade 232 relative to the soil-hardnessgauge wheel 236.

The angle θ is sent to a CPU 246 which executes an algorithm todetermine corresponding pressure values for the planting row unit 204. Aminimum angle θmin is equal to angle θ when both the blade 232 and thesoil-hardness gauge wheel 236 are on the soil surface, e.g., whenpassing over very hard soil conditions or a concrete floor. A depthvariable Z indicates a desired blade depth, i.e., blade 232 penetrationinto the soil. The angle θ is directly proportional to the depthvariable Z, which has a range between an actual (or current) depth valueZact and a theoretical depth value Ztheor.

By way of comparison, in the soil-hardness device 202 of the currentembodiment a controllable pressure P3, which is applied to thesoil-hardness device 202, is varied, but the angle θ between the blade232 and the soil-hardness gauge wheel 236 is maintained generallyconstant, with the blade 232 penetrating the soil at a desired bladedepth Z. In contrast, in the soil-hardness device 102 described above inreference to FIGS. 4A-4C the difference between the blade 132 and thewheel 136 is varied (e.g., distances X1 and X2), but the pressureapplied to the soil-hardness device 102 is maintained generallyconstant.

According to one aspect of the algorithm illustrated in FIG. 5B, theangle θ is measured (270A) and the actual depth value Zact is calculated(270B). Based on the actual depth value Zact and an inputted theoreticaldepth value Ztheor (270C), a determination is made whether the actualdepth value Zact is equal to the theoretical depth value Ztheor (270D):

If Zact=Ztheor=>end   Equation 3

If the actual depth value Zact is equal to the theoretical depth valueZtheor (i.e., Zact=Ztheor), the algorithm ends (until the next value isreceived) (270H). Optionally, if angle θ is less than minimum angle θmin(i.e., θ<θmin), algorithm ignores changes because those values typicallyillustrate that the soil-hardness sensing device 202 has hit a rock.

If the actual value of the depth variable Z is greater than thetheoretical value of the depth variable Z (i.e., Zact>Ztheor) (270E),the controllable pressure P3 that is being applied to the soil-hardnessdevice 202 is decreased until the actual value of the depth variable Zis equal to the theoretical value of the depth variable Z (i.e.,Zact=Ztheor) (270F):

If Zact>Ztheor=>decrease P3 until Zact=Ztheor   Equation 4

If the actual value of the depth variable Z is smaller than thetheoretical value of the depth variable Z (i.e., Zact<Ztheor), then thecontrollable pressure P3 is increased until the actual value of thedepth variable Z is equal to the theoretical value of the depth variableZ (i.e., Zact=Ztheor) (270G):

If Zact<Ztheor=>increase P3 until Zact=Ztheor   Equation 5

Thus, according to this algorithm, the desired depth Z of the blade 232is maintained constant by varying the pressure P3 in response todetected changes in the angle θ. To vary the pressure P3, a user-definedvariable M (similar to the user-defined variables K and J describedbelow) is increased or decreased to modify an actual value P3act of thepressure P3 until the desired depth variable Z is achieved. As such,assuming that a theoretical value P3theor of the pressure P3 is beingapplied to the blade 232 when the desired depth Ztheor is achieved, andfurther assuming that P3theor is directly proportional to M*P3act, M ismodified until M*P3act is equal to P3theor (and, consequently, thedesired depth variable Z is achieved). For example, if the depthvariable Z is too small, i.e., the blade 232 is running too shallow intothe soil (e.g., the blade 232 is moving through a heavily compacted soilarea), as detected by a change in the angle θ, M is increased until theactual pressure value P3act is equal to the theoretical value P3theor.Once the theoretical value P3theor is reached, the increased pressureforces the blade 232 into the soil at the desired depth. Furthermorechanges to the pressure P1 and the pressure P2 can be effected based onM*P3act being directly proportional to P1 and P2.

According to another aspect of the algorithm, illustrated in FIG. 5C, iffeedback is desired from the row-unit gauge wheel 216, to verify thatthe system is performing as desired (e.g., to verify that theappropriate pressure values are being applied to the planting row unit204), a weight variable W is set in accordance with a desired weight. Inthis example, the pressure P1 applied to the hydraulic actuator 220 ofthe planting row unit 204 is directly proportional to a user-definedvariable K multiplied by the pressure P3 applied to the soil-hardnessdevice 202 (i.e., P1 is directly proportional to K*P3).

A signal S4 (illustrated in FIG. 5A), which is directly proportional tothe weight variable W, is outputted by a gauge wheel load sensor 280(illustrated in FIG. 5A) and averaged over a time period Tgauge. Aftermeasuring the actual weight value Wact (272A) and receiving thetheoretical weight value Wtheor (272B), a determination is made whetherthe actual weight value Wact is equal to the theoretical weight valueWtheor (272C):

If Wact=Wtheor=>end   Equation 6

If the actual weight value Wact is equal to the theoretical weight valueWtheor (i.e., Wact=Wtheor), the algorithm ends (272G) until the nextmeasurement.

If the actual weight value Wact is greater than the theoretical weightvalue Wtheor (i.e., Wact>Wtheor), then the user-defined variable K isdecreased (272E) until the actual weight value Wact is equal to thetheoretical weight value Wtheor:

If Wact>Wtheor=>decrease K   Equation 7

If the actual weight value Wact is less than the theoretical weightvalue Wtheor (i.e., Wact<Wtheor), then the user-defined variable K isincreased (272F) until the actual weight value Wact is equal to thetheoretical weight value Wtheor:

If Wact<Wtheor=>increase K   Equation 8

The user-defined variable K can be set manually by a user orautomatically via a load pin 282.

Similarly, referring to FIG. 5D, the pressure P2 applied to therow-cleaner unit 222 can be adjusted by adjusting a user-definedvariable J. Specifically, in this example, the pressure P2 is directlyproportional to the user-defined variable J multiplied by the pressureP3 (i.e. P2 is directly proportional to J*P3). After measuring theactual weight value Wact (274A) and receiving the theoretical weightvalue Wtheor (274B), a determination is made whether the actual weightvalue Wact is equal to the theoretical weight value Wtheor (274C):

If Wact=Wtheor=>end   Equation 9

If the actual weight value Wact is equal to the theoretical weight valueWtheor (i.e., Wact=Wtheor), the algorithm ends (274G) until the nextmeasurement.

If the actual weight value Wact is greater than the theoretical weightvalue Wtheor (i.e., Wact>Wtheor), then the user-defined variable J isdecreased (274E) until the actual weight value Wact is equal to thetheoretical weight value Wtheor:

If Wact>Wtheor=>decrease J   Equation 10

If the actual weight value Wact is less than the theoretical weightvalue Wtheor (i.e., Wact<Wtheor), then the user-defined variable J isincreased (274F) until the actual weight value Wact is equal to thetheoretical weight value Wtheor:

If Wact<Wtheor=>increase J   Equation 11

The user-defined variable J can also be set manually by a user orautomatically via the load pin 282.

Referring to FIGS. 6A and 6B, an agricultural system 300 includes atractor 301, two soil-hardness sensing devices 302A, 302B, a plantingdevice 303, and a plurality of planting row units 304A-304L, which areconfigured in a side-by-side arrangement. In this example, each of theplanting row units 304A-304L has at least one respective control ValveA-L, which is adjustable based on signals received from thesoil-hardness sensing devices 302A, 302B.

The tractor 301 moves at a speed Q, pulling the soil-hardness sensingdevice 302A, 302B, the planting device 303, and the planting row units304A-304L along a soil area that includes five soil areas 305A-305E.Specifically, the soil areas 305A-305E includes a top outside area 305A,a top wheel area 305B, a central area 305C, a bottom wheel area 305D,and a bottom outside area 305E. The top wheel area 305B and the bottomwheel area 305D have soil conditions that are harder than the topoutside area 305A, the central area 305C, and the bottom outside area305E. The harder soil conditions are caused by the wheels of the tractor301 and/or planting device 303, which form a compacted path as thetractor 301 moves along the soil area. Thus, each of the top wheel area305B and the bottom wheel area 305D are areas compacted by the wheels ofvehicles.

A first soil-hardness sensing device 302A controls only the planting rowunits 304E, 304H that are positioned inside the compacted paths of thetop wheel area 305B and the bottom wheel area 305D. A secondsoil-hardness sensing device 302B controls all the other planting rowunits 304A-304D, 304F-304G, and 304I-304L, i.e., all the planting rowunits positioned outside the compact paths of the top wheel area 305Band the bottom wheel area 305D (and within the top outside area 305B,the central area 305C, and the bottom outside area 305E). Optionally,any number of soil-hardness sensing devices and any number of plantingrow units can be used. For example, each of the planting row units304A-304L can have its own designated soil-hardness sensing device.

The soil-hardness sensing devices 302A, 302B are positioned at adistance D in front of the planting row units 304A-304L. Optionally,each of the soil-hardness sensing devices 302A, 302B can be positionedat a different distance in front of the planting row units 304A-304L.For example, the first soil-hardness sensing device 302A can bepositioned at a distance X1 in front of the planting row units 304A-304Land the second soil-hardness sensing device 302B can be positioned at adistance X2 in front of the planting row units 304A-304L. As currentlyillustrated in FIGS. 6A-6B, the distances X1 and X2 are equal to eachother (being effectively distance D). Furthermore, the firstsoil-hardness sensing device 302A is positioned inside the compactedpath of the bottom wheel area 305D and the second soil-hardness sensingdevice 302B is positioned inside the bottom outside area 305E (i.e.,outside the compacted path of the bottom wheel area 305D).

The soil-hardness sensing devices 302A, 302B and the attached plantingrow units 304A-304L are generally configured to sense soil conditionsand adjust corresponding hydraulic pressures of Valves A-L as describedabove in reference to FIGS. 1-5. The configuration of having multiplesoil-hardness sensing devices 302A, 302B increases precision inadjustment of hydraulic pressures, based on current soil conditions,because it accounts for differences between compacted and non-compactedpaths in a field that is being planted. Thus, for example, thesoil-hardness sensing devices 302A, 302B provides signals tocorresponding control valves for increasing and/or decreasing hydraulicpressures of the planting row units 304A-304L.

The soil-hardness sensing devices discussed above can be remotelycontrolled. For example, the soil-hardness sensing devices 302A, 302Bcan be remotely controlled with a handheld radio-frequency remotecontroller. By way of example, the remote controller can be used tomanually increase and/or decrease the hydraulic pressures in one or moreof the soil-hardness sensing devices 302A, 302B.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrated embodiment and thatthe present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributes thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are therefore intended to be embraced therein.

1. An agricultural system comprising: an agricultural row unit movableon a field between a first soil condition and a second soil condition,the first soil condition having a different soil hardness than thesecond soil condition; a down-pressure actuator applying pressure to therow unit, the down-pressure actuator initially applying a first pressureassociated with the first soil condition; a soil-hardness sensing devicepositioned at a distance D forward of the row unit, the soil-hardnesssensing device outputting a soil-hardness change signal when detecting achange from the first soil condition to the second soil condition; andat least one memory device storing instructions that, when executed byat least one processor, cause the down-pressure actuator to change, inresponse to receiving the soil-hardness change signal, the firstpressure to a second pressure when the row unit encounters the secondsoil condition.
 2. The agricultural system of claim 1, wherein thesoil-hardness change signal is determined based on the distance D and avelocity Q of the row unit.
 3. The agricultural system of claim 1,wherein the down-pressure actuator includes a hydraulic actuator.
 4. Theagricultural system of claim 3, further comprising a control valve forcontrolling, in response to the soil-hardness change signal, flow ofhydraulic fluid to the hydraulic actuator.
 5. The agricultural system ofclaim 1, wherein the at least one processor is located on the row unit.6. The agricultural system of claim 1, wherein the soil-hardness sensingdevice includes a first linear position sensor coupled to a blade and asecond linear position sensor coupled to a wheel gauge, thesoil-hardness change signal being determined in part based on relativemotion between the blade and the wheel gauge as measured by the firstlinear position sensor and the second linear position sensor.
 7. Theagricultural system of claim 1, wherein the soil-hardness sensing deviceincludes a blade arm, a gauge wheel arm, and an angular encoder, theangular encoder measuring relative angular motion between the blade armand the gauge wheel arm, the soil-hardness change signal beingdetermined at least in part based on the relative angular motion.
 8. Theagricultural system of claim 1, further comprising a side-by-sidearrangement of agricultural row units connected to a towing frame, therow units including a first group of row units and a second group of rowunits, the first group of row units being positioned inside a compactedpath formed by wheels of a towing vehicle, the second group of row unitsbeing positioned outside the compacted path.
 9. The agricultural systemof claim 8, further comprising: another soil-hardness sensing devicepositioned outside the compacted path, the soil-hardness sensing devicebeing positioned inside the compacted path; a first set of controlvalves for controlling, in response to the soil-hardness change signal,flow of hydraulic fluid to the first group of row units; and a secondset of control valves for controlling, in response to anothersoil-hardness change signal outputted by the another soil-hardnesssensing device, flow of hydraulic fluid to the second group of rowunits.
 10. An agricultural system comprising: a plurality of row unitspositioned in a side-by-side arrangement and attachable to a towingframe, the plurality of row units being movable on a field between soilconditions of varying soil hardness, the plurality of row unitsincluding a first group of row units positioned inside a towing-vehiclewidth and a second group of row units positioned outside thetowing-vehicle width; a hydraulic actuator mounted on and applying downpressure to each row unit of the plurality of row units, the hydraulicactuator being adjustable to a frequency F and initially applying afirst down pressure; a first soil-hardness sensing device positioned ata distance X1 forward of at least one row unit of the first group of rowunits, the first soil-hardness sensing device outputting a firstsoil-hardness change signal when detecting a change in soil hardnessinside the towing-vehicle width; a second soil-hardness sensing devicepositioned at a distance X2 forward of at least one row unit of thesecond group of row units, the second soil-hardness sensing deviceoutputting a second soil-hardness change signal when detecting a changein soil hardness outside the towing-vehicle width; and at least onememory device storing instructions that, when executed by one or moreprocessors, cause the hydraulic actuator of respective ones of theplurality of row units to change, in response to receiving at least oneof the first soil-hardness change signal and the second soil-hardnesschange signal, the first pressure to a second pressure.
 11. Theagricultural system of claim 10, wherein each of the first soil-hardnesschange signal and the second soil-hardness change signal is determinedbased on the distance D and a velocity Q of the plurality of row units.12. The agricultural system of claim 10, wherein the distance X1 isequal to the distance X2.
 13. The agricultural system of claim 10,wherein at least one of the one or more processors is mounted on each ofthe plurality of row units.
 14. The agricultural system of claim 10,further comprising a first set of control valves and a second set ofcontrol valves, the first set of control valves controlling, in responseto the first soil-hardness change signal, flow of hydraulic fluid to thefirst group of row units, the second set of control valves controlling,in response to the second soil-hardness change signal, flow of hydraulicfluid to the second group of row units.
 15. The agricultural system ofclaim 10, further comprising a control valve individually coupled to arespective row unit of the plurality of row units, the control valvecontrolling flow of hydraulic fluid in response to receiving at leastone of the first soil-hardness change signal and the secondsoil-hardness change signal.
 16. An agricultural system comprising: anagricultural row unit movable on a field between a first soil conditionand a second soil condition, the first soil condition having a differentsoil hardness than the second soil condition; a down-pressure actuatorapplying pressure to the row unit, the down-pressure actuator initiallyapplying a first pressure associated with the first soil condition; avelocity sensing device for detecting a velocity Q of the row unit; asoil-hardness sensing device positioned at a distance D forward of therow unit and encountering the second soil condition at an initial timeprior to the row unit encountering the second soil condition at asubsequent time, the soil-hardness sensing device outputting asoil-hardness change signal when detecting a change from the first soilcondition to the second soil condition; and at least one memory devicestoring instructions that, when executed by at least one processor,cause the down-pressure actuator to change, in response to receiving thesoil-hardness change signal and based on the velocity Q and the distanceD, the first pressure to a second pressure at the subsequent time whenthe row unit encounters the second soil condition.
 17. The agriculturalsystem of claim 16, further comprising a control valve for controlling,in response to the soil-hardness change signal, flow of hydraulic fluidto a hydraulic actuator of the down-pressure actuator.
 18. Theagricultural system of claim 16, wherein the at least one processor islocated remote from the row unit.
 19. The agricultural system of claim16, further comprising one or more other agricultural row unitsoperatively connected to a towing frame in a side-by-side arrangementwith the row unit.
 20. The agricultural system of claim 16, furthercomprising a handheld radio-frequency remote controller for controllingthe soil-hardness sensing device.
 21. An agricultural system comprising:a towing frame for attachment to a towing vehicle draw bar; anagricultural row unit attached to the towing frame in a trailingposition relative to a moving direction on a field, the row unit beingmovable between a first soil condition and a second soil condition, thefirst soil condition having a different soil hardness than the secondsoil condition, the row unit including a down-pressure actuator forapplying pressure to the row unit, the down-pressure actuator initiallyapplying a first pressure associated with the first soil condition; asoil-hardness sensing unit attached to the towing frame in a forwardposition relative to the moving direction on the field, thesoil-hardness sensing unit being positioned at a distance D forward ofthe row unit, the soil-hardness sensing unit detecting soil-hardnesschanges and outputting a soil-hardness change signal when detecting achange from the first soil condition to the second soil condition; andat least one memory device storing instructions that, when executed byat least one processor, cause the down-pressure actuator to change, inresponse to receiving the soil-hardness change signal, the firstpressure to a second pressure when the row unit encounters the secondsoil condition.
 22. The agricultural system of claim 21, wherein thesoil-hardness sensing unit is an integral unit separate from the rowunit, the soil-hardness sensing unit detecting the soil-hardness changesindependent of the row unit.
 23. The agricultural system of claim 21,wherein the soil-hardness change signal is determined in real time. 24.The agricultural system of claim 21, wherein the soil-hardness changesignal is based on the distance D and a velocity Q of the row unit. 25.The agricultural system of claim 21, wherein the soil-hardness sensingunit is an integral unit separate from the row unit, the soil-hardnesssensing unit detecting the soil-hardness changes independent of the rowunit and in real time based on the distance D and a velocity Q of therow unit.